docs: document environment variable support in ape-config.yaml files (

ApeWorX#2148)

docs/userguides/config.md

@@ -19,6 +19,16 @@ However, here is a list of common-use cases requiring the `ape-config.yaml` file
 2. Setting up project dependencies: See the [dependencies](#dependencies) section.
 3. Declaring your project's plugins: See the [plugins](#plugins) section.
 
+**Environment Variables**: `ape-config.yaml` files support environment-variable expansion.
+Simply include environment variables (with the `$` prefix) in your config file and Ape will automatically expand them.
+
+```yaml
+plugin:
+ secret_rpc: $MY_SECRET_RPC
+```
+
+This helps keep your secrets out of Ape!
+
 ## Contracts Folder
 
 Specify a different path to your `contracts/` directory.

src/ape/utils/misc.py

@@ -216,7 +216,7 @@ def load_config(path: Path, expand_envars=True, must_exist=False) -> dict:
  and is able to be load.
 
  Returns:
- Dict (dict): Configured settings parsed from a config file.
+ dict: Configured settings parsed from a config file.
  """
  if path.is_file():
  contents = path.read_text()

tests/functional/test_config.py

@@ -1,3 +1,4 @@
+import os
 from pathlib import Path
 from typing import Optional, Union
 
@@ -39,6 +40,33 @@ def test_model_validate_path_contracts_folder():
  assert cfg.contracts_folder == str(path)
 
 
+def test_validate_file():
+ value = "pathtowherever"
+ with create_tempdir() as temp_dir:
+ file = temp_dir / "ape-config.yaml"
+ file.write_text(f"contracts_folder: {value}")
+ actual = ApeConfig.validate_file(file)
+
+ assert actual.contracts_folder == value
+
+
+def test_validate_file_expands_env_vars():
+ secret = "mycontractssecretfolder"
+ env_var_name = "APE_TEST_CONFIG_SECRET_CONTRACTS_FOLDER"
+ os.environ[env_var_name] = secret
+
+ try:
+ with create_tempdir() as temp_dir:
+ file = temp_dir / "ape-config.yaml"
+ file.write_text(f"contracts_folder: ${env_var_name}")
+
+ actual = ApeConfig.validate_file(file)
+ assert actual.contracts_folder == secret
+ finally:
+ if env_var_name in os.environ:
+ del os.environ[env_var_name]
+
+
 def test_deployments(networks_connected_to_tester, owner, vyper_contract_container, project):
  _ = networks_connected_to_tester # Connection needs to lookup config.